The invention relates to the field of disk positioning during recording and/or playing an optical disk.
The invention relates to a clamping device for a disc-shaped information carrier having a central clamping opening, which clamping device is provided with a supporting member for the information carrier, a clamping member which can be displaced from a first position, in which the clamping member clamps the information carrier against the supporting member close to the clamping opening, to a second position in which the clamping member releases the information carrier, and a lifting member which co-operates with the clamping member and can be displaced from a first position, in which the lifting member is recessed relative to the supporting member, to a second position in which the lifting member is in a raised position relative to the supporting member.
The invention also relates to a scanning device for scanning information on a disc-shaped information carrier, which scanning device is provided with a table for the information carrier which can be rotated about an axis of rotation, a clamping device for clamping the information carrier on the table, and a scanning unit which can be displaced with respect to the table.
The invention also relates to the field of disk positioning during recording and/or playing an optical disk.
A clamping device of the type mentioned in the opening paragraphs is known from WO 93/01598. Said known clamping device can suitably be used in a box-shaped holder, for example, for a CD. The clamping member of the known clamping device comprises a number of clamping elements which can be displaced, while undergoing elastic deformation, from their first positions to their second positions. In order to clamp a CD in the holder, the central clamping opening of the CD must be pushed past the clamping elements, thereby causing the clamping elements to be displaced, by the central clamping opening, from their first positions to their second positions. After the central clamping opening has gone past the clamping elements, the clamping elements are displaced from their second positions to their first positions under the influence of the elastic deformation forces in the clamping elements, so that the CD is clamped by the clamping device. The lifting member of the known clamping device comprises a number of lifting arms which can be displaced, thereby also undergoing elastic deformation, from their first positions to their second positions. The known clamping device is further provided with a centrally arranged operating member by means of which the CD can be removed from the clamping device. To achieve this, the user must press the operating member, thereby causing the operating member to simultaneously move the clamping elements from their first positions to their second positions and the lifting arms from their first positions to their second positions. As a result, the CD is released by the clamping elements and lifted from the clamping device by the lifting arms. In this manner, a user-friendly operation of the clamping device is obtained.
The above citations are hereby incorporated in whole by reference.
A drawback of the known clamping device resides in that the clamping elements are pressed against the inner edge of the central clamping opening of the information carrier under the influence of said elastic deformation forces, when the central clamping opening is pressed past the clamping elements during providing the information carrier in the clamping device. As a result, the information carrier may be damaged near the central clamping opening. Said drawback of the known clamping device is particularly unfavorable if the known clamping device is used to clamp a DVD comprising two discs which are attached to one another. Under the influence of said pressure forces on the central clamping opening, the two discs may become detached, causing the DVD to become useless.
It is an object of the invention to provide a clamping device of the type mentioned in the opening paragraphs, in which the above-mentioned drawback of the known clamping device is precluded.
To achieve this, the clamping device in accordance with the invention is characterized in that the clamping device is provided with a first locking member, which locks the clamping member in its second position if the lifting member is not substantially in its first position, and a second locking member which locks the lifting member in its first position if the clamping member is not substantially in its second position. During placing an information carrier in the clamping device in accordance with the invention, the lifting member is displaced to its first position by the information carrier. Since the first locking member locks the clamping member in its second position if the lifting member is not substantially in its first position, the clamping member can only be displaced from its second position to its first position if the lifting member is substantially in its first position and the information carrier rests on the supporting member. In this manner, it is precluded that, during placing the information carrier in the clamping device, the clamping member contacts the information carrier before said information carrier rests on the supporting member. Since the second locking member locks the lifting member in its first position if the clamping member is not substantially in its second position, the lifting member can only be moved from its first position to its second position if the clamping member is substantially in its second position. In this manner, it is precluded that, during lifting and removing the information carrier from the clamping device, the clamping member contacts the information carrier. Since it is precluded, in this manner, that both during placing the information carrier in the clamping device and during removing the information carrier from the clamping device, the clamping member contacts the information carrier, it is precluded that, during placing the information carrier in and/or removing it from the clamping device, said information carrier is damaged near the central clamping opening by the clamping member.
A particular embodiment of a clamping device in accordance with the invention is characterized in that the clamping device is provided with means for exerting a pre-stressing force on the lifting member, said pre-stressing force being directed from the first position of the lifting member to the second position of the lifting member. If the lifting member is released by the second locking member, then the lifting member is displaced from its first position to its second position under the influence of said pre-stressing force, so that the information carrier is automatically lifted from the clamping device. By virtue thereof, the ease of use of the clamping device is improved.
A further embodiment of a clamping device in accordance with the invention is characterized in that the lifting member includes a number of lifting arms each extending substantially in a radial direction with respect to the information carrier, which lifting arms are provided, near a first end portion, with a supporting element for the information carrier, and which lifting arms are tiltable, near a second end portion, about a tilting axle extending substantially in a tangential direction with respect to the information carrier. By virtue thereof, a simple and practical construction of the lifting member is obtained.
Yet another embodiment of a clamping device in accordance with the invention is characterized in that the tilting axle of each of the lifting arms is formed by an elastically deformable hinge, the hinges jointly supplying the pre-stressing force exerted on the lifting member. As a result, said pre-stressing force is obtained in a simple and practical manner, and the number of parts of the clamping device is reduced.
A particular embodiment of a clamping device in accordance with the invention is characterized in that the clamping member includes a number of clamping elements each extending in a direction transverse to the information carrier, which clamping elements are provided with a clamping surface near a first end portion, and are tiltable, near a second end portion, about a tilting axle extending substantially in a tangential direction with respect to the information carrier. In this manner, a simple and practical construction of the clamping member is obtained.
A further embodiment of a clamping device in accordance with the invention is characterized in that the clamping member comprises a number of clamping elements which each extend in a direction substantially parallel to the information carrier, which are provided, near an end portion, with a clamping surface and can be swiveled about a swivel axle extending substantially perpendicularly to the information carrier. This too results in a simple and practical construction of the clamping member.
Yet another embodiment of a clamping device in accordance with the invention is characterized in that the clamping elements are coupled to a common operating member which can be displaced in a direction perpendicular to the information carrier, said clamping elements being jointly displaceable from their first positions to their second positions by a displacement of the operating member. Since the clamping elements can be jointly displaced from their first positions to their second positions by displacing the operating member, the ease of use of the clamping device is further improved.
A particular embodiment of a clamping device in accordance with the invention is characterized in that the clamping device is provided with further means for exerting a pre-stressing force on the operating member in a displacement direction of the operating member which corresponds to a displacement of the clamping elements from their second positions to their first positions. By virtue thereof, the ease of use of the clamping device in accordance with the invention is considerably increased. To clamp the information carrier into the clamping device, the user only has to place the information carrier on the supporting member. As a result, the lifting member is displaced into its first position, so that the clamping member is released from its second position by the first locking member, the clamping elements are displaced, under the influence of said pre-stressing force, from their second positions to their first positions, and the information carrier is clamped against the supporting member.
A further embodiment of a clamping device in accordance with the invention is characterized in that the clamping device is provided with an electromagnetic actuator for displacing the operating member. This further embodiment of the clamping device in accordance with the invention can very suitably be used in a scanning device for scanning information present on the information carrier. The electromagnetic actuator is controllable, for example, by means of an electrical control unit of the scanning device.
Yet another embodiment of a clamping device in accordance with the invention, in which the clamping device includes a number of clamping elements which can each be tilted about a tilting axle extending substantially in a tangential direction with respect to the information carrier, is characterized in that the first locking member is provided with a stop surface which is provided on the operating member and extends substantially parallel to the information carrier, while each of the lifting arms is provided, near its second end portion, with a locking element pertaining to the first locking member, which locking element serves to co-operate with the stop surface. This results in a simple and practical construction of the first locking member.
A particular embodiment of a clamping device in accordance with the invention, in which the clamping member includes a number of clamping elements which can each be tilted about a tilting axle extending substantially in a tangential direction with respect to the information carrier, is characterized in that the second locking member is provided with a further stop surface, which is provided on the operating member and extends substantially perpendicularly to the information carrier, while each one of the lifting arms is provided, near its second end portion, with a further locking element pertaining to the second locking member, which locking element serves to co-operate with the further stop surface. In this manner, a simple and practical construction of the second locking member is obtained.
A further embodiment of a clamping device in accordance with the invention, in which the clamping member includes a number of clamping elements which can each be swiveled about a swivel axle extending substantially perpendicularly to the information carrier, is characterized in that, near a further end portion, the clamping elements bear against a stop surface of the operating member while being subjected to a pre-stress, which stop surface comprises a conical portion extending transversely to the information carrier and serving to co-operate with the further end portions of the clamping elements. This results in the clamping elements being coupled in a simple and practical manner to the common operating member.
Yet another embodiment of a clamping device in accordance with the invention, in which the clamping member includes a number of clamping elements which can each be swiveled about a swivel axle extending substantially perpendicularly to the information carrier, is characterized in that the first locking member comprises a cylindrical portion of the stop surface of the operating member, which cylindrical portion extends perpendicularly to the information carrier and serves to co-operate with the further end portions of the clamping elements, said cylindrical portion connecting to the conical portion of the stop surface near an end portion of the conical portion where the diameter of the conical portion is largest, while each one of the lifting arms is provided, near its second end portion, with a locking element pertaining to the first locking member, which locking element serves to co-operate with a recessed portion provided in the operating member. In this manner, a practical and simple construction of the first locking member is obtained.
A particular embodiment of a clamping device in accordance with the invention, in which the clamping member includes a number of clamping elements which can each be swiveled about a swivel axle extending substantially perpendicularly to the information carrier, is characterized in that the second locking member comprises a further cylindrical portion of the stop surface of the operating member, which further cylindrical portion extends perpendicularly to the information carrier and connects to the conical portion of the stop surface near a further end portion of the conical portion where the diameter of the conical portion is smallest, while each one of the lifting arms is provided, near its second end portion, with a further locking element pertaining to the second locking member, which locking element serves to co-operate with the further cylindrical portion and a further recessed portion provided in the further cylindrical portion. This results in a practical and simple construction of the second locking member.
A scanning device of the type mentioned in the opening paragraphs is characterized in that the clamping device used therein is a clamping device in accordance with the invention. The above-described advantages of the clamping device in accordance with the invention manifest themselves in a particular manner in the scanning device in accordance with the invention.
These and other aspects of the invention will be apparent from and elucidated with reference to the embodiment(s) described hereinafter.